The invention relates in general to sea platform anchors and in particular to a new and useful universal joint provided with shoes at the bottom end of a connection between a surface platform and a foundation anchored on the bottom of the sea as well as to a method for replacing the shoes.
Such surface platforms for depths down to 300 m and for heavy seas with strong storms, as they prevail particularly in the Baltic Sea, require an extremely great engineering effort, if they are to be laid out for a 30-year stability. The problem is therefore to ensure the operating safety of the universal joint used on the bottom of the sea under these difficult conditions for this period of time. It has already been suggested to equip such a universal joint with replaceable shoes which have a coat of PTFE. Measures must be taken here to protect the ball surface on which the shoes slide from corrosion by the sea water. For this purpose it has been suggested to use an air or gas filled bell which is open at the bottom. Nevertheless the free sliding ball surfaces can be contaminated by foreign bodies from the sea water, which can get into the sliding gap. In this way and also by normal wear due to abrasion, the sliding layers of the shoes can become unusable.